If I may, my take is that if I do not believe the technique will work, it usually tends to work better than if I believe it will work. Perhaps it is linked to the whole idea of "letting go".

A "do not care about the outcome, or believe the technique will work, just let it go and see what happens" - kind of state.

My take would be just the other way:
If you are not completely convinced of what you are doing, if will tend to fail. Best example: yonkyo. If you have any doubt about getting the right point, it will rather not work.

Although, I would agree to saying that one should not carry preconceptions on how to do a technique, instead adapting it to the situation. Maybe thatīs what you meant, Nick ?